Question 1

For a standard normal distribution, determine that probability that z is between 0 and 1.48; that is, find P(0 < z < 1.48).

Accepted Answer

A) .4265 
B) .4793 
C) .4850 
D) .4949 
E) .4306 
A) .4265 
B) .4793 
C) .4850 
D) .4949 
E) .4306

Question 2

North Dakota Mining (NDM) describes its estimate of the amount of oil it will produce next year from its western North Dakota operations with a normal distribution.The distribution is centered on 5.2 million barrels and has a standard deviation of .7 million barrels.According to this distribution, how likely is it that NDM's production will be between 4.8 and 6.0 million barrels?

Accepted Answer

A) .3944 
B) .4162 
C) .6406 
D) .5596 
E) .5886 
A) .3944 
B) .4162 
C) .6406 
D) .5596 
E) .5886

Question 3

At Netflix, the time it takes for a returned DVD to be re-filed and for the next DVD to be submitted for shipping to the customer follows a bell-shaped pattern, with a mean of 194 seconds and a standard deviation of 42 seconds.In 25% of the cases, "turnaround" time is less than how many seconds.

Accepted Answer

A) 156.4 
B) 165.9 
C) 122.3 
D) 222.1 
E) 219.5 
A) 156.4 
B) 165.9 
C) 122.3 
D) 222.1 
E) 219.5

Question 4

Dallas Green Homes uses a normal curve to estimate next year's demand.The distribution has a mean of 163 units and a standard deviation of 36 units.According to this demand distribution, how likely is it that demand will be less than 80 units?

Accepted Answer

A) .0362 
B) .0551 
C) .0104 
D) .0989 
E) .1127 
A) .0362 
B) .0551 
C) .0104 
D) .0989 
E) .1127

Question 5

The useful life (in years) of a shingled roof in Oregon has a uniform distribution described by the probability density function below.What proportion of roofs have a useful life of between 28.5 years and 29.5 years?   1/10 for values of x between 25 and 35
F(x) =
0 everywhere else

Accepted Answer

A) .15 
B) .10 
C) .30 
D) .25 
E) .20 
A) .15 
B) .10 
C) .30 
D) .25 
E) .20

Question 6

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that more than 67,000 cubic feet are extracted?

Accepted Answer

A) .6734 
B) .7546 
C) .6219 
D) .7830 
E) .8907 
A) .6734 
B) .7546 
C) .6219 
D) .7830 
E) .8907

Question 7

Approximately 95.5% of the values in a normal distribution will be within two standard deviations of the distribution mean.

Accepted Answer

A) True 
 B)False

Question 8

Suppose that the amount of time it takes to develop a new iPhone app is normally distributed with an average of 8 weeks and a standard deviation of 2 weeks.Fill in the blank in the following sentence: "There is a 25% probability that development time will be between how many weeks and 8 weeks."

Accepted Answer

A) 2.0 
B) 6.0 
C) 6.7 
D) 7.8 
E) 8.6 
A) 2.0 
B) 6.0 
C) 6.7 
D) 7.8 
E) 8.6

Question 9

Random variable x has a uniform distribution defined by the probability density function below.Determine the mean (expected value) of x.   1/100 for values of x between 200 and 300
F(x) =
0 everywhere else

Accepted Answer

A) 220 
B) 280 
C) 220.0 
D) 250 
E) 290 
A) 220 
B) 280 
C) 220.0 
D) 250 
E) 290

Question 10

US smartphone owners aged 18 to 24 send an average of 2,022 text messages per month (Source: Businessinsider.com, 2013).Suppose that the random variable "monthly text messages sent" is normally distributed.If exactly 20 percent of smartphone owners aged 18 to 24 send 3000 or more texts per month, what is the standard deviation of the random variable "monthly test messages sent"?

Accepted Answer

A) 404 
B) 978 
C) 1,164 
D) 1,881 
E) 2,196 
A) 404 
B) 978 
C) 1,164 
D) 1,881 
E) 2,196

Question 11

For a standard normal distribution, determine that probability that z is between -1.1 and +1.4; that is, find P(-1.1 < z < 1.4).

Accepted Answer

A) .6549 
B) .7335 
C) .7835 
D) .8023 
E) .8772 
A) .6549 
B) .7335 
C) .7835 
D) .8023 
E) .8772

Question 12

What proportion of values in a normal distribution will be above 2.33 standard deviations to the right of (or above) the mean?

Accepted Answer

A) .0802 
B) .0126 
C) .0221 
D) .0099 
E) .0398 
A) .0802 
B) .0126 
C) .0221 
D) .0099 
E) .0398

Question 13

For a continuous uniform probability distribution, the probability is proportional to the interval's width.

Accepted Answer

A) True 
 B)False

Question 14

The waiting time before a caller is able to speak to a customer service representative at Chase Bank is exponentially distributed, with an average waiting time of 2.5 minutes How likely is it that a caller will wait between 4 and 5 minutes?

Accepted Answer

A) .1623 
B) .0666 
C) .1265 
D) .1892 
E) .0934 
A) .1623 
B) .0666 
C) .1265 
D) .1892 
E) .0934

Question 15

The search time for a particular search term on Google is defined by the probability density function below, where x = the random variable "time to produce a result in milliseconds".Determine the probability that the search will take between 251 and 251.5 milliseconds. 1/5 for values of x between 250 and 255
  f(x) =
0 everywhere else

Accepted Answer

A) .20 
B) .156 
C) .125 
D) .225 
E) .10 
A) .20 
B) .156 
C) .125 
D) .225 
E) .10

Question 16

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that less than 110,000 cubic feet are extracted?

Accepted Answer

A) .9871 
B) .8974 
C) .9443 
D) .8257 
E) .9028 
A) .9871 
B) .8974 
C) .9443 
D) .8257 
E) .9028

Question 17

At Netflix, the time it takes for a returned DVD to be re-filed and for the next DVD to be submitted for shipping to the customer follows a bell-shaped pattern, with a mean of 194 seconds and a standard deviation of 42 seconds.What proportion of the "turnaround" times are between 200 and 220 seconds?

Accepted Answer

A) .1767 
B) .1986 
C) .2540 
D) .3121 
E) .2242 
A) .1767 
B) .1986 
C) .2540 
D) .3121 
E) .2242

Question 18

The average fee per student (an amount that includes activities fees, technology fees, curriculum fees, etc.) at four-year colleges is $1043.The fee charges are normally distributed with a standard deviation of $68.What proportion of students pay fees less than $1100?

Accepted Answer

A) .7995 
B) .8325 
C) .9167 
D) .8442 
E) .8168 
A) .7995 
B) .8325 
C) .9167 
D) .8442 
E) .8168

Question 19

Over a number of years, the average annual rate of return for Fidelity's Capital Appreciation mutual fund has been .17 with a standard deviation of .35.Assume annual returns are approximately normally distributed around the average rate.Using this historical information as the basis for the calculation, there is a 20% probability that this fund will have a return greater than or equal to how much?

Accepted Answer

A) -.124 
B) .198 
C) .464 
D) .3732 
E) -.293 
A) -.124 
B) .198 
C) .464 
D) .3732 
E) -.293

Question 20

Over a number of years, the average annual rate of return for Fidelity's International Capital Appreciation mutual fund has been .035 with a standard deviation of .031.Assume annual returns are approximately normally distributed around the average rate.If you use this historical information as the basis for your calculations, the probability that this fund will produce a positive return is:

Accepted Answer

A) .1292 
B) .8718 
C) .1571 
D) .7882 
E) .8534 
A) .1292 
B) .8718 
C) .1571 
D) .7882 
E) .8534

For a standard normal distribution, determine that probability that z is between 0 and 1.48; that is, find P(0 < z < 1.48).

At Netflix, the time it takes for a returned DVD to be re-filed and for the next DVD to be submitted for shipping to the customer follows a bell-shaped pattern, with a mean of 194 seconds and a standard deviation of 42 seconds.In 25% of the cases, "turnaround" time is less than how many seconds.

Dallas Green Homes uses a normal curve to estimate next year's demand.The distribution has a mean of 163 units and a standard deviation of 36 units.According to this demand distribution, how likely is it that demand will be less than 80 units?

The useful life (in years) of a shingled roof in Oregon has a uniform distribution described by the probability density function below.What proportion of roofs have a useful life of between 28.5 years and 29.5 years? 1/10 for values of x between 25 and 35 F(x) = 0 everywhere else

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that more than 67,000 cubic feet are extracted?

Approximately 95.5% of the values in a normal distribution will be within two standard deviations of the distribution mean.

Suppose that the amount of time it takes to develop a new iPhone app is normally distributed with an average of 8 weeks and a standard deviation of 2 weeks.Fill in the blank in the following sentence: "There is a 25% probability that development time will be between how many weeks and 8 weeks."

Random variable x has a uniform distribution defined by the probability density function below.Determine the mean (expected value) of x. 1/100 for values of x between 200 and 300 F(x) = 0 everywhere else

For a standard normal distribution, determine that probability that z is between -1.1 and +1.4; that is, find P(-1.1 < z < 1.4).

What proportion of values in a normal distribution will be above 2.33 standard deviations to the right of (or above) the mean?

For a continuous uniform probability distribution, the probability is proportional to the interval's width.

The waiting time before a caller is able to speak to a customer service representative at Chase Bank is exponentially distributed, with an average waiting time of 2.5 minutes How likely is it that a caller will wait between 4 and 5 minutes?

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that less than 110,000 cubic feet are extracted?

The average fee per student (an amount that includes activities fees, technology fees, curriculum fees, etc.) at four-year colleges is $1043.The fee charges are normally distributed with a standard deviation of $68.What proportion of students pay fees less than $1100?

An Introduction to Statistics

Descriptive Statistics I: Elementary Data Presentation and Description

Descriptive Statistics II: Additional Descriptive Measures and Data Displays

Probability

Discrete Probability Distributions

Statistical Inference: Estimating a Population Mean

Interval Estimates for Proportions, Mean Differences and Proportion Differences

Statistical Hypothesis Testing: Hypothesis Tests for a Population Mean

Hypothesis Tests for Proportions, Mean Differences and Proportion Differences

Basic Regression Analysis

Multiple Regression

F Tests and Analysis of Variance

Experimental Designonline Only

Chi-Square Tests

Filters

Exam 6: Continuous Probability Distributions

For a standard normal distribution, determine that probability that z is between 0 and 1.48; that is, find P(0 < z < 1.48).

At Netflix, the time it takes for a returned DVD to be re-filed and for the next DVD to be submitted for shipping to the customer follows a bell-shaped pattern, with a mean of 194 seconds and a standard deviation of 42 seconds.In 25% of the cases, "turnaround" time is less than how many seconds.

Dallas Green Homes uses a normal curve to estimate next year's demand.The distribution has a mean of 163 units and a standard deviation of 36 units.According to this demand distribution, how likely is it that demand will be less than 80 units?

The useful life (in years) of a shingled roof in Oregon has a uniform distribution described by the probability density function below.What proportion of roofs have a useful life of between 28.5 years and 29.5 years? 1/10 for values of x between 25 and 35 F(x) = 0 everywhere else

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that more than 67,000 cubic feet are extracted?

Approximately 95.5% of the values in a normal distribution will be within two standard deviations of the distribution mean.

Suppose that the amount of time it takes to develop a new iPhone app is normally distributed with an average of 8 weeks and a standard deviation of 2 weeks.Fill in the blank in the following sentence: "There is a 25% probability that development time will be between how many weeks and 8 weeks."

Random variable x has a uniform distribution defined by the probability density function below.Determine the mean (expected value) of x. 1/100 for values of x between 200 and 300 F(x) = 0 everywhere else

For a standard normal distribution, determine that probability that z is between -1.1 and +1.4; that is, find P(-1.1 < z < 1.4).

What proportion of values in a normal distribution will be above 2.33 standard deviations to the right of (or above) the mean?

For a continuous uniform probability distribution, the probability is proportional to the interval's width.

The waiting time before a caller is able to speak to a customer service representative at Chase Bank is exponentially distributed, with an average waiting time of 2.5 minutes How likely is it that a caller will wait between 4 and 5 minutes?

The amount of natural gas that Taylor Exploration extracts daily at its Cane Creek site in Utah has a normal distribution, with an average of 82,300 cubic feet and a standard deviation of 12,400 cubic feet.On a randomly selected day, how likely is it that less than 110,000 cubic feet are extracted?

The average fee per student (an amount that includes activities fees, technology fees, curriculum fees, etc.) at four-year colleges is $1043.The fee charges are normally distributed with a standard deviation of $68.What proportion of students pay fees less than $1100?

An Introduction to Statistics

Descriptive Statistics I: Elementary Data Presentation and Description

Descriptive Statistics II: Additional Descriptive Measures and Data Displays

Probability

Discrete Probability Distributions

Statistical Inference: Estimating a Population Mean

Interval Estimates for Proportions, Mean Differences and Proportion Differences

Statistical Hypothesis Testing: Hypothesis Tests for a Population Mean

Hypothesis Tests for Proportions, Mean Differences and Proportion Differences

Basic Regression Analysis

Multiple Regression

F Tests and Analysis of Variance

Experimental Designonline Only

Chi-Square Tests

Filters